Scientists from the CSIRO Wealth from Oceans National Research Flagship chooses 50 gulper sharks, swellsharks and green eye dogfish near Port Lincoln, South Australia, to test the conservation value and fitted acoustic tags on them. They designed a closed area to track shark movement and study the reason of their depletion. These species comes under the Environment Protection and Biodiversity Conservation Act 1999.
Dr Alan Williams, CSIRO Wealth from Oceans Flagship scientist, told that half of the fish harvested in Australia’s south-east fishery come from a thin belt of water along the south-eastern continental shelf at depths of 200-700 metres. This rich belt is home to several shark species vulnerable to over-fishing. Williams added that the fishery has taken necessary measures to reduce its impact on sharks by putting in place a network of three closed areas located off South Australia, Tasmania and New South Wales.
According to Williams it is very important to assess the optimum size and location of such protected areas and for this complete knowledge of sharks habitat and movement should be known such as how much time the sharks spend there, what the seabed habitats are like, and what role they play in the ecology of the sharks. For example, the sharks may rely on shelter in rough habitats, and these are scarce.
The scientists caught the sharks and tagged from the South Australian Research and Development Institute (SARDI) Marine Research Vessel Ngerin and later they some were released at the surface while others were lowered to the seabed in large cages fitted with video surveillance systems to monitor their recovery. Williams said that such experiment is expensive and important to provide total information about the balance between maintaining fisheries and protecting the marine ecosystem.
